I have a PT 50DL54. Changed the light bulb recently after 4 years of use. Soon after, vertical lines appeared on screen. There are 10 sets of 9 vertical lines together across the entire screen. I can see and hear the TV, but with these lines. Same for DVD and same for other inputs. Tried calling psonic, but they just give me instructions that I have already tried. Any advice or info you can provide? thanks